ZXY-3529 Permalloy Audio Isolation Transformer, 1+1:1 / 4:1 Turns Ratio, 10 Hz-40 kHz, Hi-POT 1250 V, 8-Pin DIP Through-Hole, 35.0 x 29.0 x 26.0 mm

1. Product Name

ZXY-3529 Permalloy audio isolation transformer. 8-pin DIP through-hole package, turns ratio 1+1:1 or 4:1, frequency range 10 Hz to 40 kHz, withstand voltage 1250 V@1 mA for 60 s, case size 35.0 x 29.0 x 26.0 mm, pin spacing 5.0 mm, nameplate rating 150/600:10K.

Overview. A single device provides complete isolation: a Permalloy shielded can, a winding structure that leads out to 8 DIP pins, and a nameplate indicating the impedance model and type name. No other components are required on the circuit board beyond the pad pattern.

There are two specification variants under the same model. They share the case, pad pattern, and pin definitions, differing only in the windings: the 1+1:1 version is for line-level coupling, and the 4:1 version is for higher input levels. The table in Chapter 5 lists both columns side by side, allowing easy comparison without cross-referencing two documents.

2. Product Features

Two turns ratio variants under one part number. 1+1:1 for line-level coupling and 4:1 for higher input levels, both using the same 35.0 × 29.0 × 26.0 mm case.

Permalloy case. High-permeability nickel-iron alloy case with rounded corners, with the magnetic circuit closed within the can, isolating external magnetic interference without requiring an additional shield.

Operating range from 10 Hz to 40 kHz. This is the overall bandwidth. Tolerances of ±0.16 dB / ±0.10 dB are specified within 20 Hz to 20 kHz, referenced to +4 dBu at 1 kHz.

Maximum input level of +22 dBu. At 1% THD, maximum 50 Hz input, +12 dBu for the 1+1:1 version.

Maximum DC resistance of 26 + 52 Ω. 1-4 side for the 1+1:1 version, maximum 70 Ω for the 5-8 side, measured at 25 °C.

Withstand voltage of 1250 V. 1 mA leakage current limit applied between windings and case for 60 s.

8-pin DIP through-hole terminals. Two rows of 4 pins each, spacing 5.0 mm, one row marked 5 6 7 8 and the other 4 3 2 1, so installation and soldering are exactly the same as other DIP devices.

Separate core and case terminals. Pins 7 and 6 bring the internal core and case to the circuit board, allowing grounding connections where design requires.

Orientation dot on the nameplate. Laser-marked ZXY audio transformer / 150/600:10K / ZXY-3529.

Custom designs available. Stock available directly from the factory, windings can be customized as needed.

The case is the shield. No additional shield can, bracket, or Permalloy wrapping is needed during assembly: the Permalloy body closes the magnetic circuit around the windings, and the circuit board only needs eight mounting holes and, if required by design, grounding pins 6 and 7.

3. Product Advantages

Protects the front-end circuit. The transformer electrically isolates input from output, so a downstream fault will not burn out the output stage of the driving line.

Eliminates ground noise. When two devices are grounded at different points, the isolation eliminates AC hum that would be introduced by a direct connection.

Supports balanced and unbalanced transmission. The same device reduces external interference in both connection methods and couples voice or data signals between circuits that cannot share a common reference ground.

Two turns ratios in the same package. Switching from a 1+1:1 to a 4:1 design keeps the PCB pad pattern, outline, and panel openings unchanged.

DIP terminals. Through-hole mounting allows for easy on-site replacement without re-validating reflow soldering temperature profiles.

Flat response across the audio band. ±0.16 dB (1+1:1) and ±0.10 dB (4:1) within 20 Hz to 20 kHz, the device does not color the signal passing through.

Since both turns ratios share the same case, switching from 1+1:1 to 4:1 in a design keeps the PCB pad pattern, panel openings, and assembly drawings unchanged. For a component typically selected late in a project after PCB layout is complete, this advantage has practical value far beyond what appears on the surface.

4. Application Areas

High-fidelity audio systems. Used between a source and preamplifier or power amplifier to eliminate audible AC hum and ground loop noise.

Home theater. Isolates processor outputs from power amplifier inputs during long cable runs.

Car audio. Disconnects the ground path between the head unit and external amplifier.

Mixing console signal isolation output. Sends console outputs to recorders, broadcast lines, or stage feeds without connecting grounds together.

Multi-channel isolated signal output. One component per channel, multiple outputs from the same chassis.

The common factor in these applications is the non-shareable ground. Once two chassis are at different ground potentials, a direct connection transmits the potential difference as hum; the transformer passes only the signal, not the potential difference, which is its entire purpose.

5. Application Specifications

Electrical data measured at 25 °C, as stated in the ZXY-3529 specification sheet.

5.1 Electrical Specifications

The overall frequency range is 10 Hz to 40 kHz; the ±0.16 dB and ±0.10 dB tolerances in the table are specified over 20 Hz to 20 kHz, referenced to +4 dBu at 1 kHz. The dielectric withstand test is 1250 V with a 1 mA leakage current limit for 60 seconds.

5.2 Construction and Mechanical Data

5.3 Winding and Pin Assignment

6. Quality and Testing Assurance

Each of the following parameters is specified at 25 °C conditions as stated in the manufacturer's specification sheet, and the device carries CCC, CE, RoHS, and UL certification marks.